Cleanup the plethora of libvirt live migration options
Cleanup the plethora of libvirt live migration options

This does a few things:

1. Ties the live_migration_tunneled and live_migration_inbound_addr
   options together in the help via "Related options" since they
   are, well, related. live_migration_inbound_addr is ignored if
   doing a tunneled live migration.

2. Removes references to live_migration_flag and block_migration_flag
   which were removed in Newton: a48b6146af93dd0cb1b43ec7d83867df8b347df2

3. Adds the parallels URI to the list in live_migration_uri.

4. Fixes a typo in live_migration_scheme where it said "schema" - it's
   not a schema, it's a URI scheme.

Change-Id: I77a0a0fe92f1d25d2e5f150d1507af5defa8043c

klmitch/nova,jianghuaw/nova,jianghuaw/nova,klmitch/nova,openstack/nova,gooddata/openstack-nova,rahulunair/nova,phenoxim/nova,vmturbo/nova,phenoxim/nova,vmturbo/nova,klmitch/nova,Juniper/nova,vmturbo/nova,Juniper/nova,rahulunair/nova,vmturbo/nova,mahak/nova,gooddata/openstack-nova,mikalstill/nova,openstack/nova,mahak/nova,mahak/nova,rahulunair/nova,Juniper/nova,jianghuaw/nova,Juniper/nova,openstack/nova,jianghuaw/nova,mikalstill/nova,klmitch/nova,gooddata/openstack-nova,mikalstill/nova,gooddata/openstack-nova